For example, an electric vehicle running with electric motor or a hybrid vehicle running with engine and electric motor together has the aforementioned power source unit mounted thereto as power source of the electric motor. This power source unit is provided with a bus bar module as recited in the PTL 1 listed below.
As shown in FIGS. 5 and 6, the bus bar module is attached to a battery assembly 102 formed in such a fashion that batteries 120 including a positive electrode 122 at one end and a negative electrode 123 at the other end are alternately and oppositely overlaid, thus connects in series the overlaid batteries with each other, and is provided with a plurality of bus bars 103 straightly arranged in two lines so as to connect in series fine plurality of batteries 120, a pair or FFCs (flexible flat cable) 104 connected with each of the bus bar 103 and wired along a arrangement direction of the plurality of bus bars 103 (wiring direction X), and a pair of cases 105 housing lire plurality of bus bars 103 and the pair of FFCs 104. As shown in FIG. 5, such the bus bar module 101, with it overlaid on a top of the battery assembly 102, has each of the bus bars 103 electrically connect electrodes 122, 123 of the adjacent batteries 120 by a nut 102A being threaded into electrodes 122, 123 of each of the batteries 120, and thus is set into the battery assembly 102.
As shown in FIG. 6, the FFC 104 is provided with a plurality of conductors 140 (1401 to 140n) separated from each other, and a cover 141 insulating and covering the plurality of conductors 1401 to 140n. The FFC 104 is arranged such that the plurality of conductors 1401 to 140n is arranged in the same direction as a direction Y of connecting piece 131 of the bus bar 103 (to be described later) upstanding.
As shown in FIG. 6, the bus bars 103 are each provide with a plate-like bus bar body 130, a connection piece 131 upstanding from the bus bar body 130 and being connected to one conductor 140n of the FFC 104.
As shown in FIG. 6, the case 105 is separately provided with a bus bar housing 151 housing the plurality of bus bars 103, and an FFC cover 152 assembled in the bus bar housing 131 and clipping and holding the FFC 104 between the FFC cover 152 and the bus bar housing 151. The bus bar housing 151 is provided with housings 153 arranged in the arrangement direction X and housing each of the bus bars 103, and a coupler 154 coupling these housings 153. The FFC cover 152 is disposed across its whole length and continued in the arrangement direction X.
The housings 153 are each provide with a rectangular placement part 153A where the has bars 103 are each placed, and four partition walls 153B upstanding from the placement part 153A, and are formed into a frame shape with bottom. Of the four partition walls 153B one located near the FFC cover 152 is provided with a slit 155 passing therethrough the connection piece 131 of the bus bar 103. This slit 155 is disposed at a middle of the one partition wall 153B.
The aforementioned conventional bus bar module 101 allows each of the bus bars 103 to be housed in each of the housing 153, and while the connection piece 131 of the bus bar 103 is inserted from the slit 155 of the housing 153 to be guided outside, the connection piece 1311 of the endmost bus bar 103 (the first bus bar 103) is joined using ultrasonic with the bottommost conductor 1041 of the FFC 104, the second connection piece 1312 of the bus bar 103 is joined using ultrasonic with the second conductor 1042 of the FFC 104, the nth connection piece 131n of the bus bar 103 is joined using ultrasonic with the nth conductor 104n of the FFC 104, and thereby the bus bars 103 are each electrically connected with the conductors 1041 to 104n of the FFC 104 different from each other.
In each the bus bar module 101 each of the bus bars 103 was insulated from outside by being surrounded by the four partition walls 153B of the housing 153 housing the bus bar 103 and by holding the FFC 104 between the bus bar housing 151 and the FFC cover 152.